The invention relates to a peristaltic pump.
Peristaltic pumps generally comprise a drive motor connected via a gearbox to drive a rotor housed in a pumphead. The rotor carries a pair of shoes or other means for engagement with a flexible tube. As the rotor rotates, the shoes deform the flexible tube to form an occlusion in the tube. As the occlusion moves along the length of the tube, fluid in the tube is forced from one end to the other.
Conventional pumps can generally be classified as either long-coupled or close-coupled pumps.
In a long-coupled pump, the drive unit is coupled to the pumphead via a coupling. Any misalignment (both angle and position) between the drive unit and the pumphead can be corrected via the coupling. However, this process is time consuming and thus costly. The coupling itself is also expensive.
With close-coupled pumps, the rotor is connected directly to the drive unit thereby eliminating the need for a coupling and the associated alignment process. However, with such a design, the drive unit itself must handle the large force exerted on the rotor while compressing the tube.
To avoid the issues associated with close-coupled pumps, the Applicant invented (see EP0881389) a direct-coupled pump in which the pumphead connects directly to the drive unit and the rotor is supported by its own hub, thereby isolating and protecting the drive unit from the forces exerted on the rotor. This allows the drive unit to use a smaller and less expensive gearbox. However, with such a direct-coupled pump, the orientation of the rotor is fixed with respect to the hub which does not allow for any angular misalignment between the components which may result from manufacturing tolerances.
It is therefore desired to provide a pump which addresses the issues of conventional direct-drive pumps and provides greater tolerance of misalignments.